Cyclone furnace



March 10, 1970 J. E. M. wEssBr-:RGy

C'CLONE FURNAGE Filed May 23, 1968 Pn/JLA,

OYHESS United States Patent O 3,499,401 CYCLONE FURNA'CE Jacob Erland Magnus Wessberg, Torslanda, Sweden, as-

signor to Aktiebolaget Gotaverken, Goteborg, Sweden, a corporation of Sweden Filed May 23, 1968, Ser. No. 731,375 Int. Cl. F23b 1/16 U-S. Cl. 110-89 1 Claim ABSTRACT OF THE DISCLOSURE Owing to the intense heat generated during the cornbustion of solid fuel in a cyclone furnace certain residues are formed, which melt, ow down through the fuel bed and congeal on the grate clogging the same. This slag is difficult to remove and usually a number of openings must be provided in the furnace wall to provide access for cleaning purposes, which is inconvenient for many purposes. In order to avoid such openings and to facilitate the cleaning of the grate the furnace proper is built on pillars a distance above the floor of the boiler room and the mechanical stoker as well as the grate structure are built on a platform which may be lowered from the furnace to make the grate fully accessible.

BACKGROUND OF THE INVENTION Typical fuels which contain impurities, which during the combustion form residues tending to melt and to clog the grate are bark and wood refuse. Especially the bark is often contaminated by particles of sand and gravel which have become lodged into the bark during the transportation. This sand and gravel is during the combustion sintered together with components in the bark.

In order to remove such slag it is necessary to provide a number of openings in the furnace walls, which must be closed by suitable doors. This raises the cost of the furnace, as the Efitting of the refractory lining is made more difficult and it is also often necessary to provide cooled frames for vthe doors to said openings.

SUMMARY OF THE INVENTION The present invention refers to an arrangement in a cyclone furnace with vertical axis and mechanical stoking apparatus by means of which the cleaning of the grate is greatly facilitated. The invention is characterized vby a number of pillars adapted to carry the cylindrical side wall of the furnace at a distance above the floor of the boiler room, a grate structure forming the bottom of the furnace and extending to said cylindrical side wall, and a platform for carrying the grate structure and the mechanical stoking apparatus. Means are provided to raise the platform to bring the grate structure into contact with a lower edge of the side wall of the furnace and to lower it therefrom, respectively, to make the surface of the grate structure available for inspection practically all around the furnace, without the necessity of providing openings in the furnace wall as well as closure means therefor.

BRIEF DESCRIPTION OF THE DRAWING The attached drawing shows one embodiment of the invention as utilized in a furnace for the combustion of bark and wood refuse and adapted to be attached to the combustion chamber of a large boiler.

DESCRIPTION OF THE PREFERRED EMBODIMENT The furnace 1 consists of a cylindrical combustion chamber with refractory walls, which at its upper part by way of a passage 2 is connected to the combustion chamber 3 of a furnace belonging to a steam boiler, where some other kind of fuel, for instance oil or pulverized coal may be burnt. The cylindrical side wall of the cyclone furnace is carried by means of a number of pillars 4 from the lloor 5 of the boiler room. The furnace is in a manner known per se provided with conduits 6 and 7 for the supply of secondary and for tertiary cornbustion air, respectively.

The bottom of the furnace is formed by a conical grate structure 8, which extends all the way to the side wall of the furnace. Below this grate an air box 9 is arranged, to which a conduit 10 for primaryfair is connected. The upper part of this box is provided with flanges 11 shaped to closely t the lower edge of the side wall of the furnace and to seal against the same in such a manner that air leakage into the furnace is prohibited. Fuel is in a manner known per se introduced into the combustion space by means of an underfeed Stoker 12 containing a screw, which feeds the fuel to a retort 13 located in the centre of the grate. Fuel is supplied to the screw by means of a conduit 14 from a suitable storage hopper. The grate structure, the air `box and the stoking apparatus are mounted on a platform 15, which by suitable means, here designed as screw jacks 16, may be raised towards the furnace wall and lowered therefrom, respectively. By lowering the platform it is possible to bring the grate below the bottom edge of the furnace wall, whereby the grate surface will be made accessible for inspection and cleaning practically all around the furnace. The primary air conduit 10 and the fuel supply conduit 14 are each provided with expansible members 17 and 18 respectively, which permit a displacement of the platform in the vertical direction without disconnecting the conduits from the air box and the stoking apparatus, respectively.

What I claim is:

1. A cyclone furnace with vertical axis and a mechanical stoking apparatus, which comprises cylindrical side walls forming the periphery of the furnace,

a number of pillars to carry the cylindrical side wall of the furnace at a distance above a furnace oor;

a grate structure forming the bottom of the furnace and extending to said cylindrical side wall,

a platform for carrying the grate structure and the mechanical stoking apparatus,

means to raise the platform to bring the grate structure into sealing contact with the lower edge of the side wall of the furnace and to lower it therefrom, respectively, to make the surface of the grate structure available for inspection,

conduits for supplying fuel and combustion air, respectively to the grate structure, and

elastic elements in said conduits permitting the displacement of the platform without disconnection of the supply conduits.

References Cited UNITED STATES PATENTS 486,067 11/1892 Allan 110-89 l685,682 10/1901 Hunt 110-88 1,064,500 6/1913 Leask 126-154 XR 2,702,013 2/ 1955 Atteberry 110-45 XR 3,289,620 12/ 1966 Heilala 110-45 KENNETH W. SPRAGUE, Primary Examiner 

